Even after Labor Day weekend, Teller troopers still using 2E callsign so it appears it's permanent. By voice recognition, yep, the only thing that changed is the letter.
I suggest 2B West talk group is indeed used for special situations but not actually geographically defined. I've heard it used for team ops on I-25 south of the Springs, LIDAR training on US24 near GMF, and most recently for the Hell's Angels visit to Cripple Creek. Also, very occasionally, routine traffic is moved to 2B West so those units involved in a dangerous situation on 2B East can have a dedicated TG and mundane activity can continue uninterrupted as well.
This passes for excitement in Teller County.